Cementing method and apparatus



A May 20, 1969 BROWN ET AL 3,444,929

CEMENTING METHOD AND APPARATUS Sheei Z of 3 Filed Aug. 31, 1966 CARLCHWA INVE AFFOR. 8

Leaf

May 20, 1969 J. R. BROWN ET AL 3,444,929

CEMENTING METHOD AND APPARATUS sheetiors Filed Aug. 31, 1966 :JOE R.BROWN CARL M. SCHM AB I N VIZNTOR.

A T TORNE Y5 y 1969 J. R. BROWN ET AL 3,444,929

CEMENTING METHOD AND APPARATUS Sheet 3 of3 Filed Aug. 31. 1966 JOE R.BROWN United States Patent 3,444,929 CEMENTING METHOD AND APPARATUS JoeR. Brown and Carl M. Schwab, Houston, Tex.; said Schwab assignor toBrown Tools, Inc., Houston, Tex., a corporation of Texas Filed Aug. 31,1966, Ser. No. 576,445 Int. Cl. E21b 37/02 US. Cl. 166-173 3 ClaimsABSTRACT OF THE DISCLOSURE A method of and an apparatus for wiping theexterior of a well pipe in a Well bore clean by reciprocating the wellpipe through a wiping surface which is in contact with the well pipeexterior and is held against movement in the well bore.

The present invention relates to a new and improved ered in the wellbore to remove the wall cake from the 0 interior surface of the wellbore to improve the bonding of the cement to the interior surface of thewell bore. Additionally, the exterior surface of the well pipe has beentreated before lowering it into the well bore in an attempt to obtainimproved bonding of the cement to the well pipe. Such treating has beenpartially successful but one of the major causes of poor bonding of thecement to the well pipe results from the coating of the exterior of thewell pipe by the drilling fluids and mud necessarily present in the wellbore when the well pipe is lowered therein to the desired position.

-It is, therefore, an object of the present invention to provide animproved cementing method and apparatus to prepare the exterior surfaceof the well pipe during cementing to improve the cement bonding thereto.

Another object is to provide a new and improved device for wiping theexterior of a well pipe in a well bore during cementing operationswithout interfering with normal cementing operations.

Another object is to provide a new and improved wiper device adapted tobe slidably mounted on a well pipe section which is to be cemented in awell bore in conjunc tion with other devices to wipe the exterior of thewell pipe while removing wall cake from the wall of the well bore.

Still another object is to provide a new and improved wiper device incombination with another device commonly used on well pipes forcementing operations,

A further object is to provide a new and improved well pipe wiper deviceadapted to be actuated by wall scratchers and centralizers during acementing operation to wipe drilling fluids from the exterior surface ofthe well pipe.

These and other objects and advantages of the present invention will beapparent from the claims and the following specification describing thepreferred form of the present invention with reference to the drawingswherein:

FIGURE 1 is a partial longitudinal sectional view through a well boreand illustrates the preferred form of wiper device of the presentinvention on a well pipe with a centralizer;

FIGURE 2 is another partial longitudinal sectional 3,444,929 PatentedMay 20, 1969 view through a well bore illustrating another form of thewiper device of the present invention incorporated into a centralizerunit;

FIGURE 3 is another partial longitudinal sectional View through a wellbore and shows another form of the wiper device of the present inventionincorporated into a wall scratcher unit;

FIGURE 4 is a cross-sectional view taken along line 44 in FIGURE 1;

FIGURE 5 is a cross-sectional view taken along line 5-5 in FIGURE 1;

FIGURE 6 is a cross-sectional view taken along line 66 in FIGURE 2;

FIGURE 7 is a cross-sectional view taken along line 77 in FIGURE 3; and

FIGURES 8, 9 and are schematic views to illustrate the operation of themethod of the present invention; FIGURE 8 showing the position of thecomponents at the commencement of an up-stroke; FIGURE 9 showing theposition of the components as wiping starts on the upstroke and FIGURE10 showing the position of the components at the completion of wiping onthe up-stroke.

The wiping device 10 of the present invention is illustrated in FIGURE Imounted around the well pipe P within the well bore B with thecomponents shown as they are run into the well bore. The centralizer Cis shown as providing the means for engaging the wiping device 10 tohold it relatively stationary so that raising and lowering of the wellpipe P produces a relative movement between the wiper device 10 and thewell pipe P, which movement causes the wiper 10 to wipe the exteriorsurface of the well pipe P in the presence of cement to improve the bondbetween the cement and the well pipe P. A scratcher S is also mounted onthe well pipe P to prepare the well bore for cementing while the wellpipe P is being cleaned.

As can be seen from FIGURES 1 and 5, the wiping device 10 includes aresilient sleeve 14 having integral, inwardly extending, annular ribs 16and the split channelshaped collar 18. The sleeve 14 is split at 20 sothat it can readily be mounted around a well pipe. The collar 18 is madein two sections which are joined together at the extremities by bolts 22and 24 to form the support around the outer periphery of sleeve 14. Eachof the collar sections is channel-shaped, having upper and lowerinwardly extending flanges 26 and 28 which retain the sleeve 14 withinthe collar 18. If desired, a portion of the exterior of sleeve 14 may besuitably bonded to the interior of one of the sections of the collar 18.The collar 18 is of a predetermined size so that when it is mounted on aWell pipe with the sleeve 14 contained therein, the inner surfaces ofthe ribs 16 are in wiping contact with the exterior surface of the wellpipe. Additionally, the collar 18 must have an outer diameter whenmounted on a well pipe P to assure engagement by the centralizer collars30 and 32.

The centralizer C illustrated in FIGURE 1 includes the two collars 30and 32 spaced from each other and connected by a plurality ofcentralizer springs 36. As shown, the centralizer collars 30 and 32 aresplit collars for ease in mounting the centralizer C on the well pipe P.Thus, with the wiping device 10 mounted around the well pipe P, thecentralizer C is mounted around the well pipe P with collar 30positioned above wiping device 10 and collar 32 positioned below wipingdevice 10. The stops 37 and 38 are secured to the well pipe P by the setscrews 40 and 42 to limit the relative longitudinal movement between thewell pipe P and the centralizer C.

In operation, the well pipe P having wiping device 10, centralizer C,stops 37 and 38 and scratcher S mounted thereon is lowered into the wellbore B to the level at which it is to be cemented. In lowering well pipeP into well bore B, the components mounted thereon assume the positionsillustrated in FIGURE 1, i.e., the centralizer C is engaged by upperstop 37 and the wiping device is in engagement with the lower collar 32of centralizer C. As in usual cementing procedures, the well pipe P isthen reciprocated longitudinally to prepare the well bore B and the wellpipe P for cementing. Such reciprocation functions to raise and lowerwall scratcher S to remove the wall cake from the walls of the well borewhich is generally necessary to provide an adequate bond of the cementto the wall of the well bore. With the present invention, thisreciprocation also accomplishes during a portion of each stroke thepreparation of a portion of the exterior of the well pipe P by thewiping action as hereinafter explained.

Referring to FIGURES 8, 9 and 10, the relative movement of the componentparts of the present invention are shown during the upward stroke of thepipe reciprocation. Two centralizers C1 and C-2, two wiper devices W-land W-Z are shown mounted on the well pipe P. Also included are thethree stops A1, A-2 and A-3 and the well scratcher S.

In FIGURE 8, the position illustrated is taken at the end of a downwardmovement of the well pipe P. As also shown in FIGURE 1, the centralizersare engaging their upper stop and the wiper devices are in engagementwith the lower collars of the centralizers.

The well pipe P, as shown in FIGURE 9, has moved upwardly a shortdistance. The wiper devices W-1 and W-2 have moved upwardly with thewell pipe P to a position engaging the upper collars of the centralizersC1 and C2. The centralizers C-1 and C-2, because of their engagementwith the well bore B, have remained stationary. The scratcher, beingshown to be secured to the well pipe P, has moved upwardly and hasscratched the wall of the well bore B.

The well pipe P has been moved upward an additional distance to reachthe position shown in FIGURE 10. The

centralizers C-1 and C-2 being positioned between stops during suchmovement remain stationary. Also, the centralizers hold the wiperdevices stationary and the well pipe P moves therethrough and a portionof its exterior has been wiped or cleaned thereby. The engagement of thestops A-2 and A-3 against the lower end of the centralizers C-1 and C-2terminates the wiping action. Further upward movement of the well pipe Pfrom the position shown in FIGURE 10 does not result in any relativemovement of the pipe with respect to the wiper devices and thecentralizers but only in a scratching action of the scratcher on thewall of the well bore B.

The downward stroke of the well pipe P is similar to the describedupward stroke. During the first portion of the downward stroke, the wellpipe P and the wiper devices move downwardly with respect to thecentralizers. When the lower collars of the centralizers engage thewiper devices, the well pipe moves through the wiper devices and iscleaned or wiped by the wiping action resulting from such relativemovement.

Generally such reciprocation of the well pipe for scratching the wellbore and cleaning the well pipe is commenced immediately proceeding orduring the placement of cement. However, whenever it becomes derisableto wipe or clean a portion of the exterior surface of a well pipe in awell bore, such cleaning may be accomplished by reciprocating the Wellpipe having thereon suitable wiping devices and a means of retaining thewiping devices stationary during at least a portion of the pipemovement.

While the entire surface of the well pipe P between stops 37 and 38 isnot wiped by the wiping device 10, a sufiicient portion of such surfaceis wiped to assure an adequate cement bond to the well pipe P.

In FIGURES 2 and 6, a modified form of the present invention isillustrated which includes two wiping devices 44 and 46 mounted in theupper and lower collars 48 and 50, respectively, of the centralizer 52.As shown,

, centralizer springs 62 connecting between the collars 48 and 50. Thesprings 62 are adapted to engage the wall of the well bore B when thecentralizer 52 is mounted around the well pipe P and lowered into theWell bore B. Stops 64 and 66 are secured to the well pipe P by setscrews 68 and 70 above and below the centralizer 52 to limit therelative longitudinal movement between the centralizer 52 and the wellpipe P. When centralizer 52 is installed around well pipe P, the ribs 58and 60 should be in wiping contact with the exterior surface of the wellpipe P. To facilitate mounting, the sleeves 54 and 56 may be split, asat 72 (FIGURE 6), and may be partially bonded to one part of the collars48 and 50.

In operation, the reciprocation of the well pipe P during cementingmoves the Well pipe P in wiping contact through the wiping devices 44and 46 to remove drilling fluids, mud and production fluids. This wipingof the exterior of the well pipe P allows the cement to come into directcontact and to set against the exterior of the well pipe P to provide animproved bonding of the cement to the well pipe.

In FIGURES 3 and 7, another form of wiping device is shown. In this formthe resilient wiping sleeve 74 having integral, inwardly extending,annular ribs 76- is installed within the internal recess 78 of the bodyof the wall scratcher 80. The wall scratcher 80 is shown mounted aroundthe well pipe P between the stops 82 and 84, which are suitably securedto the well pipe P by set screws 83 and 85, and includes a plurality ofscratching fingers 86 adapted to engage the wall of the well bore B inthe usual manner. The resilient sleeve 74 may be split, as at 88, andpartially bonded in the recess 78 to facilitate installation of the uniton the well pipe P.

During a portion of the longitudinal reciprocation of the well pipe Pfor wall scratching, the well pipe moves through the wall scratcheruntil the scratcher is engaged by the stops 82 and 84. This relativemovement accomplishes the wiping of drilling fluids, mud and productionfluids from the exterior surface of the well pipe P by the movement ofthe well pipe relative to the wiping contact of the ribs 76. Aspreviously described, this wiping of the exterior surface of the wellpipe P results in an improved cement bond. It is contemplated that awiping device having inwardly projecting, longitudinally extending ribsin wiping contact with a well pipe may be used with scratcher deviceswhich require rotation to remove wall cake rather than reciprocation.

From the foregoing the various forms of the improved wiping device ofthe present invention and the improved method of cementing whichimproves the cement bond to a well pipe being cemented in a well borehave been described and explained. The wiping device of the presentinvention, when installed on a well pipe, together with means forengaging and retaining the device stationary, wipes the exterior surfaceof the well pipe in the presence of cement responsive to the normalraising and lowering for scratching the well bore, and such wipingassures an adequate bond of the cement to the well pipe.

The foregoing disclosures and description of the invention areillustrative and explanatory thereof, and various changes in the size,shape and materials, as well as in the details of the illustratedconstruction, may be made within the scope of the appended claimswithout departing from the spirit of the invention.

5 What is claimed is: 1. A Wiper device for cleaning a well pipe in awell bore, comprising:

a resilient wiping sleeve, and

a centralizer having two collars connected by a plurality of centralizersprings mounted on a well pipe,

said sleeve being mounted in one of said collars of said centralizer toposition said sleeve around the well pipe in wiping contact with theexterior surface of said well pipe,

said centralizer retaining said sleeve relatively stationary withrespect to a well bore whereby movement of said well pipe produces arelative movement of said pipe with respect to said sleeve to clean aportion of the exterior surface of said well pipe.

2. A wiper device according to claim 1, including:

a second resilient wiper sleeve having inwardly extending ribspositioned in the other collar of said centralizer.

3. A wiper device for cleaning a well pipe in a well bore, comprising:

a resilient wiping sleeve,

a collar having a recess for receiving said resilient wiping sleeve,

said collar being mounted around a well pipe and being sized to retainthe inner surface of said sleeve in wiping contact with the exterior ofsaid Well pipe, and

a centralizer having two collars connected by a plurality of centralizersprings,

said centralizer mounted on said well pipe with said wiping sleevecollar between the centralizer collars for retaining said sleeverelatively stationary with respect to a well bore whereby movement ofsaid well pipe produces a relative movement of said pipe with respect tosaid sleeve to clean a portion of the exterior surface of said wellpipe.

References Cited UNITED STATES PATENTS JAMES A. LEPPINK, PrimaryExaminer.

U.S. Cl. X.R. 15-104.4

